The former Emmerdale actress had to try the food during the chef's morning masterclass and told White that she had enjoyed the dish.
But when he turned his back she spat the kidneys out into the bin. After disposing of one kidney, Marco asked her to try another.
When she informed him that she had already eaten one, he said: "Have another one. I thought you wanted to win the show. Chew. Break it down in your mouth and see how it dissolves the heat. "
She later confessed: "He was watching and I thought right come on bang out those acting skills now. Mmm mm.
"Oh it was just ridiculously spicy, the sauce was vile I don't like hot things - it nearly blew my head off. I think I'll have a visit to the toilet later."
The footage will be shown on Hell's Kitchen tonight at 10pm on ITV1.